Thiophosphate esters, their insecticidal application, and process of preparation



United States Patent The present invention relates to a new class ofthiophosphate esters, having the general formula:

Z P-S-CHr-C ON I R O 1';

Y-CN

wherein R and R" are alkyl radicals having a low molecular Weight, i.e.not more than six carbon atoms each, R being different from or the sameas R", X is an oxygen or sulfur atom; Z is hydrogen or a low molecularweight alkyl radical and Y is a short straight or branched aliphatichydrocarbon chain preferably having no more than six carbon atoms. Thecompounds included in the above general Formula I have outstandinginsecticidal activity both with respect to domestic parasites (forinstance, flies) and with respect toagricultural pests (for instance,aphids). Another interesting property of these compounds is theiractivity against mites in their various stages of development, as wellas against their eggs.

They can be used in various ways. Generally, it is bet ter to dilutethem with solid, liquid or semisolid carriers, adding wetting, adhesive,dispersing or emulsifying substances.

They can also be distributed in air by fumigation, or in the form ofaerosols. Other compounds having an insecticidal activity (such asphosphoric esters, DDT and gammahexane) can also be added to thethiophosphate esters of the invention.

The compounds having the general Formula I may be prepared by reacting asalt of a corresponding dialkylthioor dialkyldithio-phosphoric acidhaving the general formula acetic acid, having the general formula:

/z Hal-OHa-JON Y--ON (III) wherein Z and Y are as defined above and Halis a chlorine, bromine or iodine atom.

Said halogen compounds can be obtained by reacting a cyanoalkylaminewith a haloacetylating agent (for instance, monochloroacetylchloride ormonochloroacetic.

anhydride).

The reaction is preferably carried out in the presence of a solvent forone or both reagents. Very suitable for this purpose are, for instance,low molecular weight 3,033,744 Patented May 8, 1962 ice (preferably nomore than five carbon atoms) aliphatic ketones which allow separation ofthe by-products and facilitate the separation of the end product.Reaction takes place at room temperature but may be carried out at 10 to100 C.; in certain cases it is convenient to heat, for a short time, to50-60 C.

Sometimes it may be convenient to use more than the stoichiometricquantity of one reagent.

The halide compound, which is formed as by-product, can be removedeither by filtration or (when the final product is insoluble in water)by adding water causing the dissolution of the inorganic salt and of theeventual excess of metallic phosphate, as well as the simultaneousprecipitation of the end product.

The separation of the end product can also be carried out by other knownmethods (solvent extraction, concentration, crystallization orchromatographic column).

The products having the general Formula I are oily liquids or, incertain cases, crystalline products soluble in common organic solvents.

Some of these products, generally the monothio-derivatives, have goodsolubility in water, which is useful for certain applications. Theinvention is illustrated but not limited by the following examples.

7 EXAMPLE 1 36 g. of de-hydrated sodium 0,0-dimethyldithi0phosphate and20- g. of N-cyanomethylamide of monochlorothus obtained is purified, theby-products being removed by continuous extraction with n-hexane.

By maintaining the residue under vacuum until a constant weight wasreached, 26.5 g. of product are obtained in the form of a straw-coloredlimpid oil, which solidifies, after a short time, at room temperature,yielding crystals having an M1. 38-40 C. (after crystallization,

from ethyl acetate and petroleum ether), of the following formula:

OHsO

N calculated=1l.02%. N found=l1.04 to 11.00%.

EXAMPLE 2 20 g. N-cyanomethylamide of monochloroacetic acid (meltingpoint 89 to 89.5 C.) are added to a solution of 37 g. potassium0,0-diethyldithiophosphate dissolved in ml. of acetone.

The reaction is slightly exothermic and rapid precipitation of KCl takesplace. After leaving it at room temperature for 2 hours, the reactionmixture is poured into half a liter of H 0, under agitation. An oilycompound separates, which solidifies completely after a short time. Thecompound, filtered by aspiration and thoroughly washed with Water,yields a white powder having a melting point of Til-71 C. The productobtained is subsequently'dissolved, at mild heat, in 70 ml. of ethylacetate. By adding 100 ml. of petroleum ether and allowing'it tocrystallize, 31 g. of a solid colorless crystalline product are obtainedhaving a melting point of 7.1.5 to 72 C. and consisting ofN-cyanomethylarnide of 0,0-diethyldithiophosphorylacetic acid of thefollowing formula:

S=PS-CH2CON C1350 CHaCN Ncalculated=9.92%; N found==9.66 to 9.65%.

EXAMPLE 3 20.8 g. of potassium 0,0-diethylmonothiophosphate and 13.2 g.of N-cyanomethylamide of monochloroacetic acid (melting point 89 to 89.5C.) are mixed in 60 ml. of acetone. The mixture is slightly warmed up tofavor the dissolution of' the reagents and is then left to stand for 2hours. It is then heated with weak refluxing of the solvent for 30minutes, cooled and filtered by aspiration in the presence of acoadjuvant (for instance, Celite). The limpid filtrate is evaporateduntil a constant weight was reached under reduced pressure.

28 g. of a limpid straw-colored oil remain consisting ofN-cyanomethylamide of 0,0-diethy1monothiophosphorylacetic'acid of thefollowing formula:

O=PSCH2CON C2350 CHrGN N calculated:l0.52%'. N found=9.91 to 9.38%.

EXAMPLE 4 36.5 g. of di-hydrated crystalilne sodium0,0-dimethyldithiophosphate and 1 9 g. of N-methyl-N-cyanomethylamide ofchloroacetic acid (boiling point at 0.4 to 0.5

' mm. Hg==135 to 140 C.) are mixed with 60 ml. of acetone; the reactionis slightly exothermic. The reaction mixture is left to stand for 15hours and then kept under reduced pressure in order to evaporate most ofthe solvent.

The residue is poured into Water, taken again with meth CHsO CH1 areobtained in the form of an oily liquid. N calculated=l0.44%. Nfound=9.80 to 9.60%.

EXAMPLE 5 35 g. of potassium 0,0-diethyldithiophosphate and 19 g. ofN-methyl-N-cyano-methylamide of chloroacetic acid (boiling point at 0.4to 0.5 mm. Hg=135 to 140 C.) are mixed in 70 ml. of acetone. Thereaction is highly exothermic. The mixture is left to stand for 15 hoursand then the KCl formed is filtered olf. The filtrate is then evaporatedunder reduced pressure. The residue, diluted with a small amount ofmethyl chloride, is then washed with H O. The organic solution, afterdrying, is evaporated under reduced pressure. an. oily liquid whichremain as residue consist of the N-methyl-N- cyanomethylamide of0,0-diethyldithiophosphorylacetic acid, and correspond to the followingformula:

EXAMPLE 6 27.2. g. of" potassium- 0,0-diethylmonothiophosphate and 19 g.of N-methyl-N-cyanomethylamide of chloroaceticacid are'mixed in 70 ml.of acetone.

The reaction mixture is slightly warmed and then left standing for 15hours.

After filtering in the presence of a coadjuvant (for instance, Celite),the limpid filtrate is concentrated under reduced pressure until aconstant weight is reached. 39 g. of a straw-colored oil remain asresidue consisting of N-cyano-methyl-N-methylamide of0,0-diethylmonothiophosphoryl aceticacid, having the following formula:

EXAMPLE 7 52 g. of crystalline di-hydrated sodium0,0-dimethyldithiophosphate and 32.1 g. of rawN-ethyl-N-cyanomethylamide of chloroacetic acid are reacted at roomtemperature in ml. of acetone. After 3 days the solvent is evaporatedand the residue is poured into ml. of H 0, whereafter it is taken upagain with 75 ml. of CH CI and then washed with H O. After drying andevaporation of the solvent, 38 g. of a liquid strawcolored oil areobtained which, when further purified by continuous washingwithn-hexane, is reduced to 28.5 g. This product consists ofN-cyanomethylN-ethylamide of 0,0-dimethyldithiophosphorylacetic acid ofthe following formula;

GHaO CzHs P-S-CHa-CO-N ll CHaO S CHzCN N calculated=9.92%. N found=9.53to 9.48%.

EXAMPLE 8 24.6 g. of potassium Qo-diethyldithiophosphate and 16 g. ofraw undistilled N-ethyl-N-cyanomethylamide of chloroacetic acid aremixed in 60 ml. of acetone. Reaction occurs with moderate development ofheat. The mixture after standing for 2 hours, is filtered by aspirationfrom KCl and after evaporating most of the acetone under reducedpressure, the remaining residue is poured into H O. The organic phase,after diluting with a small quantity of methylene chloride, is washedagain with H O. Upon evaporation of the solvent under reduced pressure,29 g. of N-ethyl-N-cyanomethylamide of 0,0-diethyldithiophosphorylaceticacid having the following formula:

are obtained in the form of a limpid yellow colored oil. Ncalculated=9.02%. N found=8.65 to 8.69%.

EXAMPLE 9 20.8 g. of potassium 0,0-diethylmonothiophosphate and 16 g. ofraw N-ethyl-N-cyanomethylamide of chloroacetic acid are reacted in 60ml. of acetone. The mixture after slight warming is left to stand for 1hour, and then heated under mild refluxing for half an hour. In

' order to separate KCl the mixture is subsequently filtered in thepresence of a coadjuvant (for instance Celite) and concentrated underreduced pressure until constant weight is reached, thus obtaining 29 g.of N-ethyl-N- cyanomethylamide of 0,0-diethylmonothiophosphorylaceticacid, in the form of a light yellow oil, having the following formula:

EXAMPLE 24 g. of chloroacetic N-methyl-N-beta-cyanoethylamide (boilingpoint at 0.2 mm. Hg=147 C.) are added to 75 ml. of a water solution ofsodium 0,0-dimethyldithiophosphate (concentration 2.5 mol/liter) whilemechanically agitating the mixture. The temperature rises spontaneouslyup to about 45 C. After agitating for 24 hours the reaction mixture isextracted with 100 m1. of CH' Cl The organic extract is washed twicewith a total amount of 80 ml. H O, then dried and evaporated underreduced pressure. The residue is purified by continuous washing withn-hexane.

After treatment under reduced pressure, 26.7 g. ofN-methyl-N-beta-cyanoethylamide of 0,0-dimethyldithiophosphoryl-aceticacid are obtained in the form of an oily liquid, having the followingformula:

/H CH3() S CH2-CH2ON N calcu1ated=9.92%. N found=9.32 to 9.29%.

EXAMPLE ll 37 g. of potassium 0,0-diethyldithiophosphate and 24 g. ofchloroacetic N-methyl-N-beta-cyanomethylamide (boiling point at 0.2 mm.Hg=l47 C.) are reacted in 75 ml. of acetone. The reaction is soexothermic as to heat the mixture-to a temperature at which the solventis refluxed. After standing for 24 hours, most of the acetone isevaporated under reduced pressure, and the residue is poured intolOO ml.of H 0, wherefrom it is mixed with 60 m1. of CHgClg- The organic phaseis then washed twice with 50 ml. of H 0. After drying and evaporatingunder reduced pressure, 40.5 g. N-methyl-N beta-cyanoethylamide of0,0-diethyldithiophosphorylacetic acid are obtained in the form of acolorless limpid oil, of the following formula:

P calculated=9.99%. P f0und=9.35 to 9.32%.

EXAMPLE l2 21 g. of potassium 0,0-diethylmonothiophosphate and 16 g. ofchloroacetic N-methyl-N-beta-cyanoethylamide (boiling point at 0.2 mm.Hg= l47 C.) are reacted in 60 ml. of acetone.

After warming, the mixture is left to stand for hours. The mixture isthen filtered by aspiration in the presence of a coadjuvant (forinstance, Celite) and evaporated under reduced pressure, thus obtainingas residue 29.5 g. of N-methyl-N-beta-cyanoethylamide of0,0-diethylmonothiophosphorylacetic acid, in the form of a limpid oil,of the following formula:

CHzCHzCN N calculated =9.s2%. N found=9.16,to 9.17%.

EXAMPLE 13 48 g. of crystallized di-hydrated sodium0,0-dimethyldithiophosphate and 32 g. of N-alpha'cy-ano-isopropylamideof monochloroacetic acid (melting point 87 to 88 C.) are reacted in 80ml. of acetone, heating initially to 40-50 C. After 3 hours most of theacetone is evaporated under reduced pressure, and the remainder ispoured into 100 ml. of H 0, wherefrom it is taken up again with-80 ml.of CH Cl then washed twice with 50 ml. of H 0, dried and evaporatedunder vacuum. The residue, consisting of a colorless limpid oil, is thenpurified by continuous washing with n-hexane. This residue, aftertreatment under vacuum, consists of 32 g. of a partially crystallizedsolid, having a melting point between 45 and 55 C., from which thedesired product N-(alpha-cyano)-isopropy1amide of0,0-dimethyldithiophosphorylacetic acid having the formula:

can be obtained. The pure product has a melting point of 57 to 59 C.(from ethyl acetate and petroleum ether). N calculated=9.92%. Nfound=9.89 to 9.70%.

EXAMPLE 14 021150 /OHa S=P-SCH2C ONHC-CN in the form of a whitecrystalline solid having a melting point of 83 to 835 C. (from ethylacetate and petroleum ether). N calculated=9.02%. N found=9.00 to 8.98%.

EXAMPLE 15 20.8 g. of potassium 0,0-diethylmonothiophosphate and 16 g.of chloroacetic N-(alphacyanofisopropylamide are reacted in 60 ml. ofacetone. After heating initially to about 50 C., the mixture is left tostand for 15 hours. The mixture is then filtered by aspiration-in thepresence of a coadjuvant (for instance Celite). The limpid filtrate,when evaporated under reduced pressure until a constant weight isreached, yields 29 g. of N-(alphacyano)isopropylamide of 0,0diethylmonothiophosphorylacetic acid, of the following formula:

CzHgO /CH3 O=PSCHi-CONH-CON CzHsO CH3 in the form of a yellow limpidoil. N calculated=9.52%. N found=9.l3 to 9.12%.

EXAMPLE 16 34.6 g. of potassium O-rnethyl-O-ethyl-dithiophosphate and19.9 g. of N-cyano-methylamide of monochloroacetic acid are mixed in ml.of acetone; the mixture thus obtained is refluxed for 20 minutes andthen left to stand for 15 hours. After this period the precipitated KClis separated by filtration and most of the solvent is evaporated underreduced pressure. The residue is poured into ml. of water, taken upagain with 60 ml. of methylene chloride and washed twice with water (50ml. each time). After drying on CaCl and evaporation of the solventunder reduced pressure, 32 g. of a slightly opalescent colorless oilwhich solidifies after a short time in the form of a waxlike solid, areobtained as a residue.

The product, crystallized from diluted methanol, and having a meltingpoint of 54-58 C., substantially consists of N-cyano-methylamide ofO-methyl-O-ethyl-dithio- I phosphorylacetic acid, having the formula:

CEaO

r *-s-cH.-c-Nn-cH.-oze CtHrO V l P calculated=11.55%.P-found=ll.12%l1.07%.

EXAMPLE 17 V 34.6 g. of potassium O-methyl-O-ethyl-dithiophosphate and24 g. of N-ethyl-N-cyanomethylamide of monochloroacetic acid are mixedin 120 ml. of acetone; the reaction is mildly exothermic. By operatingSubstantially as described in Example 16, 30 g. of a light wellow oil(DEE-1200; n P=l.5262) are obtained. It consists substantially ofN-ethyl-N-cyanomethylamide of O-methyl- O-ethyl-dithiophosphorylaceticacid, having the formula:

CHQO C2115 PSCH2CON ii I (32:51:50 S CHzCN P calculated: 10.46%. Pfound=l0.72-10.69%.

EXAMPLE 18 34.6 g. of potassium 0-methyl-O-ethyl-dithiophosphate and24g. of N-methyl-N-beta-cyanoethylamide of monochloroacetic acid aremixed in 150 ml. of acetone; the reaction is mildly exothermic. Byoperating substantially as described in Example 16, 41.5 g. of acolorless oil;

having a specific gravity of D =1.248 and an index of refraction of n=l.5353, are obtained. The oil consists substantially ofN-methyl-N-beta-cyanoethylamide ofO-methyl-O-ethyl-dithiophosphorylacetic acid, of the formula:

P calculated=9.46%. P found=8.848.75%.

EXAMPLE 19 23.1 g. of potassium O-methyl-O-ethyl-dithiophosphate and 16g. of N-alpha-cyanoisopropylamideof monochloroacetic acid are mixed in100 ml. of acetone. By operating substantially as described in Example16, 25 g. of an oil having D 1.223 and n =1.5233, are obtained. This oilconsists substantially of N-(alpha-cyano)-isopropylamide ofO-methyl-O-ethyl-dithiophosphorylacetic acid, of the formula:

CHsO CH2 ll czHsO S CH:

, Pcalculated=10.46%. Pfound=10.51%-10.47%.

The specific activity of the compounds obtained in Examples 1 to 19 isillustrated by the following examples:

EXAMPLE 20 Activity against domestic fly bytopic application: The dosesnecessary to obtain a 50% death rate with acetone solutions of theactive products on S-day old female flies, in tests of topic applicationby microsyringe, are as follows; 7

Product obtained in the example: LD 50, 'y/fly 8 Product obtained in theexample: LD 50, v/fiy 9 0.85 10 3.5

Activity against Aphis fabae: The concentrations necessary to obtain adeath rate, upon testing plants in-" fested with parthenogenetic apterfemales, of A phis fabae, bred with artificial light, and treating understandardized conditions with aqueous dispersions of the active prod uctssuitably formulated are as follows.

Product obtained in the example: Concentration, p..p.m.

Activity against Tetranychus telarius by contact: The concentrationsnecessary to obtain a 95% death rate on a mixed population of T.zelarius with mites at difierent development stages, bred on bean, withartificial light, treating the plantsunder standardized conditions withaqueous dispersions of active products suitably formulated, are asfollows.

Activity against Aphis fabae by radical systems way: The doses necessaryto obtain a 95 %-death rate after 6 days of parthenogenetic apterfemales of'A. fabae bred. with artificial light on broad bean plantshaving theradi cal apparatus dipped in an aqueous dispersion of theactive product suitably formulated, and avoiding, by conventional means,any eventual systems action, are as follows.

Product obtained Concentration,

in the example: p.p.m.

Activity against eggs of Tetranychus telarius: The con centrationsnecessary to obtain a 50% non-opening of Tetranychus telarius eggs, laidon bean plants, by treat- Table 3 mg the same, under standardizedcond1t1ons, with aqueous dispersions of the active products, suitablyformulated,

Dosage, Percent LD 05, are as follows- Products ppm mortality p.p.m.oiA.S. at the of A.S. Product obtained Concentration, 'whhmn in theexample: ppm.

14 44 N-eyanomethylamide of O-niethyl-O- g 83 3g 64ethyl-ditltiophosphorylacetic acid..." 50 80 4 1125 12N-ethyl-N-eyanomethylamide of 0- 10 00 100 For products having Rdifierent from R", the following g gg g ethyldlthmpmspmm 5.00 98 4 1activity tests were carried out: j39 3% Activity against domestic fiy bytopic application: In 15 N-methyl-N-betacyanoethylamlde of 1.25 100tests of topic application by microsyringe Of all d 81% 2 0.7 solutionof the active produtcs on 5 days old domestic 0.16 15 flies, the averagepercent mortalities shown in Table 1 l a g g r wgy i g 88% 108 me y '6 y10 mp 0S1) ory were obtained at the th hour. acetic acid g2 1 Table 1 200.25 13 P t The treatment of mite eggs gave the average percent B20911Product ig mortziiity 9x1 mortahtles reported in Table 4.

'y y att e 'y y 20th hour Table 4 97 Percent N-eyanomethylamide ofO-methyl-O- 76 D n osage mortality LD 50 ethyl dithiophosphorylaceticacid... (L112 Products f X t l i i g: 0 a e 0 6th (1a ttf 't tt f t t tif 1- ts y me y- -e y-i iop osp ory- 77 No yanomethylamide ofO-methyl-O- acetic amd ethyl-dithlophosphorylaeetic acid..- g 770 56 6N-ethgl-lqgyaglomittlilylalllllideh of1 O- me y -e i0 os cry ace-N-rnethyl-N-betacyanoethylamide of 3 00 100 tic acid Y EUR 3 26 1, 000

-m t y y ophosp oryl- 89 1 25 N-methyl-N-betacyano-ethylamideof 5 1acetic acid 73 0-methyl-O-ethyldithiophosphoryl- 1 p 54 acetic acid 11500' T h i N-(alpha-cyano)isopropy1amide of O- ita; i i11 t i -iiti1 ici i1opi ri- $.83 32 I g yhyldrthto hos horylace- 188 3 46 acetic acid2. 25 86 1.3 50 53 1.32 2% 25 19 Systemic activity by root absorption:The hypogeous portion of young bean plants infested by aphids (Aphis fi' agalFst g f if' i g $3. 2? fabae) '15 introduced into colored glasspots containing a a a i i 0 ls aqueous dispersions of the product to betested. The pots M g on ma P z T i i g are kept under room conditionsfavorable to the insects in? an aqugous lSP EI'SODflS e sulta y ormatetafq for 7 days, following each day the mortality of the aphidsshances F g f' i i 3%; i living on the epigeous part of the plants andtaking the ii g i t tame at 6 WT definitive reading at the 7th day (seeTable 5 s a ce Table 5 Table 2 Dosage Percent LD 95 Products ppm.mortality ppm: Dosage, Percent LD 95, 0f 1L3. at the Of AB. Productpiping. mortality 7th day 0 a e i 55 24mm! N-cyanomethylamide ofO-methyl-O- 0.250 100 ethyl-dithiophosphorylacetic acid.-. 0.2

10100 100 N-cyanomethylamide of O-methyl-O- 5.00 98NethylN'cyanom?thylamide of 100 ethyl-dithiophosphorylacetic acid".-- 2.50 67 4. 1 .19thyl'o'ethyldlthlophosphoryl 00 95 1 1. 25 32 amd 8- 32 iN-ethyl-N-cyauomethylamlde of O- 8' N-methyl-N-betacyanoethylamide of 0:250 100 grghgilxgig -ethy1-d1th1ophosphoryl- 1 81 7 6O-rrethyli-O-ethyl-dithiophosphoryl- 2. 50 32 1.25 4 0-031 4 h N-(alha-cyano)1sqpropylam1de of O- 1.000 100 gi gg g Pifiggfffiggfig? 238 8gmeiiiyl-O-ethyldlthiophosphoryl are 0.500 99 phoryl-acetic acid 2. 15413 mg acid 3 0. 062 16 N-(alpha-cyan0)-isopropylamide of 0- 6g methyl 0ethyldithiophosphoryl 5O 97 acid ,2 3 We claim:

1. A thiophosphate ester of the formula:

no a Activity against Tetranychus telarius: Treating by imfi"' mersion amixed population of adult mites on bean plants RO X under standardconditions with an aqueous dispersion in which R and R" ar alkylradicals ea h having not of the suitably formulated substances to beexamined, more than six carbon atoms, X is an atom taken from the theaverage percent mortalities reported in Table 3 were obtained at the24th hour:

than six carbon atoms.

2. A compound as defined in claim 1, the R, R"radicals being taken fromthe group consisting of methyl and ethyl, the X substituent beingsulfur.

' 3: Acompound as defined inclaim 1, the R',-R" radi cals being takenfrom the group consisting of methyl and ethyl, the X substituent beingoxygen.

4. N-methyl-N-cyanomethylamide of 0,0-diethyldithiophosphorylaceticacid, corresponding to the formula:

CH3 P-S-CHCON I C2H5O S CHzCN 5. N cyanomethylamide of0,0-.dimethyldithiophosphorylacetic acid, corresponding to the formula:

CHaO

CHzCN 7. N-(alpha-cyano)-isopropylamide of O,O-diethyldithiophosphorylaceticacid, corresponding to the formula:

8. N-(alphacyano) -isopropylamide' of 0,0-diethyl- 1 2monothiophosphorylacetic acid, corresponding to the formula:

9; N-cyanomethylamide of O-methyl 0 ethyl-dithiophosphorylacetic acid.

10. N ethyl N cyanomethylamide of O methyl-O-cthyl-dithiophosphorylacetic acid 11. N methyl N betacyanoethylamideof O-methyl- O-ethyl-dithiophosphorylacetic acid.

12. N (alpha cyano) isopropylamide of O-mcthyl- O-ethyldithiophosphorylacetic acid.

13. In the art of controlling insect pests in their various stages ofdevelopment and their eggs, the improvement comprising applying at thelocality infested by the pests a thiophosphate ester of the formula:

RO z

P-S-CHPCON-Y-CN IL RO x in which R and R" are alkyl radicals each havingnot more than six carbon atoms, X is an atom taken from the groupconsisting of sulfur and oxygen, Y is a divalent saturated aliphatichydrocarbon radical having not more than six carbon atoms, and Z istaken from the class consisting of hydrogen andalkyl radicals having notmore than six carbon atoms, either as single active element or mixedwith one or more known compounds taken from the'class consisting ofpesticides, fertilizers and carriers,

' said pests being taken from the class consisting of flies,

aphids, and mites.

14. The invention defined in claim 13, the R, R" radicals being takenfrom the group consisting of'methyl and ethyl, the X substituent beingsulfur.

15. The invention defined in claim 13, the R, R" radicals being takenfrom the group consisting of methyl and ethyl, the X substituent beingoxygen.

References Cited in the file of this patent UNITED STATES PATENTS2,494,283 Cassady et a1 Jan. 10, 1950

1. A THIOPHOSPHATE ESTER OF THE FORMULA: